Pyknocytosis, Infantile

Infantile pyknocytosis is a benign transient process; patients present during the first few days of life with jaundice, mild hepatosplenomegaly, and moderately severe hemolytic anemia. Reticulocyte counts range from 10-20%, and up to 50% of red blood cells resemble acanthocytes. Transfused red blood cells acquire the same pyknocytic morphology and are destroyed prematurely, indicating extrinsic causation. Causative mechanisms have not been elucidated.